I know the Rolleicord Vb takes 'Bayonet I' fit lenses and one of them is. The problem is that the other isn't.

Like I say though, they come in and old case that is moulded to fit them and the paperwork has both numbers for the lenses. From this im guessing they are a set but I don't understand why one of them doesn't fit.

The 'Bayonet I' lens does fit perfectly. Slides in and clicks snuggly on both camera lenses. The other... well doesnt do anything. It isnt threaded, doesn't slide or clip on. Its also slightly smaller.

I meant are you sure that lens set was made for that camera? There are probably cameras out there with a bayonet on the taking lens and something different on the viewing lens. It sounds like you need to look for a lens set that has two bayonet mounts.

Its just that the amount of searching ive done shows that the Rolleicords and Rolleiflexes use Bayonet I and Bayonet II fittings for both lens and this seems to span over a good few years and models for both cameras.

I think the best idea is going to be just to get the same item again and discard the two lenses that i cant use.

Is it likely that two +2 close up lens, not manufactured at the same time will both be the same. As in have the same affect/magnification?

Actually, all you need is one lens. Mount the camera on your favorite tripod. Determine the number of crank rotations you need to raise the taking lens to the same height as the viewing lens was before cranking.

Focus and frame with the lens on the viewing lens. Transfer the lens. Crank. Expose.